EMERGÊNCIA E MORFOLOGIA DE SEMENTES DE PLÂNTULAS DE MAMOEIRO SOB DIFERENTES CONDIÇÕES DE SUBSTRATO E DE ARMAZENAMENTO

Abstract

This work aims to analyze the influence of different storage environments and substrates on the emergence of papaya seedlings. The work was carried out in the municipal nursery of the municipality of Capanema, in partnership with the Federal Rural University of the Amazon, located in the aforementioned educational institution. To carry out the study, papaya fruits of the Hawaii cultivar were collected, in a commercial cultivation on an agricultural property located in the KM 2 community of Pará-Maranhão, a rural area in the municipality of Capanema, located in the Caetés microregion, in the Northeast of Pará, with geographic coordinates of 01° 11' 45” S, 47° 10' 51” W. The experimental design was completely randomized where two experiments were carried out: the first experiment was three types of substrates: Sawdust (T1), sawdust + washed sand (T2) and pure washed sand (T3). Each evaluated substrate consisted of three replications of 20 papaya seeds each and the variables analyzed were: percentage of seedling emergence (PE), and from this, the emergence speed index (IVE) was calculated. In the second experiment, seeds were packed in each kraft paper and stored in three environments, such as: Refrigerator (±4°C), Freezer (±18°C) and Natural environment (±27°C) and the variables analyzed were the percentage of emergence (PE) and the calculated emergence speed index (IVE), whose daily assessments were carried out every 45 days after sowing. The emergence of papaya seedlings sown to carry out the work began after 13 days, and at 45 days the germination percentage ranged from 68% to 85%. There was a significant difference for the variables leaf width, leaf area, Root Length and Fresh Mass of the Aerial Part, where in all these variables the Washed White Sand treatment presented the best result. The variables Seedling Height and Leaf Length, in turn, differed significantly only for the sawdust substrate, where it presented the worst result, when compared with the Washed White Sand and Sand+Saw treatments, which behaved statistically the same. The Washed White Sand substrate is the most recommended for the production of papaya seedlings, as it provided considerably higher values ​​for the Germination Percentage variable. Furthermore, this substrate promoted better initial development of seedlings, statistically differing and presenting satisfactory results in the following morphological variables: Leaf width (LF), leaf area (AF), root length (CR), fresh mass of the aerial part (MFPA), seedling height (AP) and leaf length (CF). 

Key-words: Earth, Sand, Sawdust, Germination, fruit plant.